Tank cap



FIG. 1 is a top plan view of a tank cap showing my new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a front elevational view thereof, the rear being a mirror image of the front shown herein;

FIG. 4 is a right side elevational view thereof, the left side being substantially a mirror image of the right side shown herein; and

FIG. 5 is an enlarged cross-sectional view thereof taken along line 5--5 of FIG. 1. 

The ornamental design for a tank cap, substantially as shown. 